Curved Mirrors: Concave, Convex and the Images They Form

<h3>What is a curved mirror?</h3><p>A <strong>curved (spherical) mirror</strong> is a piece cut from a hollow sphere. There are two kinds:</p><ul><li><strong>Concave mirror</strong> &mdash; reflecting surface curves inward. It <strong>converges</strong> (brings together) parallel light rays at the principal focus.</li><li><strong>Convex mirror</strong> &mdash; reflecting surface bulges outward. It <strong>diverges</strong> (spreads out) parallel rays and always forms a small, upright (virtual) image.</li></ul><h3>Parts of a spherical mirror</h3><ul><li><strong>Pole (P):</strong> the centre of the mirror's surface.</li><li><strong>Centre of curvature (C):</strong> the centre of the sphere the mirror came from.</li><li><strong>Principal focus (F):</strong> the point where parallel rays meet (or appear to come from).</li><li><strong>Focal length (f):</strong> distance from the pole to the focus.</li></ul><p>A concave mirror can form real or virtual images depending on how far the object is, while a convex mirror always gives a diminished, upright, virtual image.</p><div class="callout"><strong>Kenyan context:</strong> The wide side mirror on a matatu is a convex mirror. It makes images smaller but shows a much wider field of view, helping the driver see boda bodas and pedestrians approaching from the side on a busy Nairobi road.</div>